how can i increase the number of my data?

Basically, i have a 1x200 .mat file, the 200 are the xs (from 0 to 200) and each x has a corresponding y value. The thing is i need my plot and data to be 1x400 from that 1x200, what is the best way to do that as the values must make sense and represent the original graphe with just more data .i just want to increase the # of data without having bad or inaccurate values.

Answer 1

[Jan]

It is not clear what you are asking for. Maybe one of these 2 idea help you:

1. Change the x values:

x = 1:10;             % Some test data, use your original signal
y = rand(1, 10);

subplot(1,2,1);
plot(x, y);
subplot(1,2,2);
plot(x * 2, y);   % Or what ever change you need in x

2. Interpolation:

xx = linspace(x(1), x(end), 2 * numel(x))
yy = interp1(x, y, xx)
plot(x, y, 'o');
hold on
plot(xx, yy, '+');

[Elias Unk]

I'll try to explain better, i have a 1x200 .mat file but i need to change the number of data to 400 keeping the same shape of my graph what has been shared above doesn't add values to my .mat file so it's not what i need.

[Jan]

@Elias Unk: I do not know what a "1x200 .mat file" is. A .mat file, in which a 1x200 double vector is stored? Then why does it matter, if this is a file? Didn't you load the file already? Then your input is a [1 x 200] vector, isn't it?

You do not add values to the .mat file, if you do not call save. The linear interpolation adds additional points. Did you try it? How does the result differ from your expectations?

Please create a small example with e.g. 4 elements. Show us some inputs and the wanted output. Do not explain, what you do not need, but what you do need.

[Elias Unk]

Basically adding additional points is all i need as you mentioned above maybe the technical term is linear interpolation and no i haven't if you can recommend the function to do so and test it it'll be great.

[Jan]

As far as I understand, interp1 is the way to go.